Originally Posted by skridlov
I have seen many references to cavitation in this thread; it seems to be a generally accepted factor in the events leading up to the accident.
Not so. Although the AAIB report mentions cavitation signs on the HP pump outlet, it is by no means clear that this damage was caused by an event immediately preceding this accident.
In my ignorance I keep thinking that if there was cavitation, where did the air/gas come from if not out of solution? And if there was cavitation in a pump, it's hardly surprising that fuel ceased to be delivered (if indeed it did cease...)
The cavities can be either air or fuel vapors. The fact that cavitation damage was apparent shows that at least some of the bubbles collapsed again on the outlet, causing abrasion. The manufacturer of the pump and experts will know whether or not it was able to sustain sufficient flow under cavitating conditions, all other things being equal. This information does not appear to be publicly available.
Could someone please suggest why the cavitation isn't a sufficient explanation in itself?
Cavitation does not happen under normal conditions in a well-designed and tried-and-tested fuel delivery system with (as the AAIB said) on-spec fuel. It has to be caused by something, which may be upstream flow restriction or excessive fuel aeration. Cavitation may then exacerbate that problem, but will not be a root cause.
Bernd